P2RX1 and acute myeloid leukemia: In contrast, overexpression of the P2x1-S388A mutant and P2x1-WT control in P2x1-null AML cells had a similar effect on cell proliferation as indicated by the in vitro colony formation assay (Fig. S5C–E) and the in vivo transplantation assay (Fig. S5F–H).